Since carbon fiber-reinforced plastic (CFRP) is much lighter than metal and has high stiffness, carbon fiber-reinforced plastic is attracting attention as a next generation composite material and can be used to make lightweight structures for automobiles, aircrafts, and the like.
Methods of processing carbon fiber-reinforced plastic is very complicated and is mainly automated, and a large amount of CFRP scrap is generated as residues after manufacture of products. However, it is difficult to discard or recycle the CFRP scrap.
A representative method of recycling CFRP scrap includes introducing CFRP scrap into a compounding product by cutting the CFRP scrap into small pieces and burning the pieces or making the pieces into a master batch, and the like. This method is not widely used due to complexity and low-efficiency thereof. In addition, since carbon fibers having a high carbon content can become a single yarn or can be broken during processing due to high tensile modulus thereof, it can be difficult to manufacture a molded article using recycled CFRP scrap including the carbon fibers. Also, such a molded article can suffer from deterioration in mechanical properties, conductivity and the like due to change of the carbon fibers into a single yarn.
Further, since carbon fibers having a high carbon content break upon preparation of spun yarn, the spun yarn has been prepared from carbon staple fibers, which are manufactured by carbonizing the carbon fibers having a high carbon content together with a polyacrylonitrile polymer at low temperature to have a low carbon content and low tensile modulus. However, this technique is not suitable as a method of recycling CFRP scrap due to complicated manufacturing processes thereof.
Therefore, there is a need for a method of economically recycling CFRP scrap without deterioration in mechanical properties, conductivity and the like.